Hybrid parallel/serial bus interface

ABSTRACT

A hybrid serial/parallel bus interface has a data block demultiplexing device. The data block demultiplexing device has an input configured to receive a data block and demultiplexes the data block into a plurality of nibbles. For each nibble, a parallel to serial converter converts the nibble into serial data. A line transfers each nibble&#39;s serial data. A serial to parallel converter converts each nibble&#39;s serial data to recover that nibble. A data block reconstruction device combines the recovered nibbles into the data block. The data block is employed by a gain controller.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of U.S. patent application Ser. No.11/151,006, filed Jun. 13, 2005 which is incorporated by reference as iffully set forth.

FIELD OF INVENTION

The present invention relates to data bus transfers. In particular, theinvention relates to reducing the number of lines to transfer bus datafor gain control.

BACKGROUND

The invention relates to bus data transfers. In particular, theinvention relates to transfer of bus data for operating a gaincontroller (GC).

One example of a bus used to transfer data is shown in FIG. 1. FIG. 1 isan illustration of a receive and transmit gain controllers (GCs) 30, 32and a GC controller 38 for use in a wireless communication system. Acommunication station, such as a base station or user equipment,transmits (TX) and receives (RX) signals. To control the gain of thesesignals, to be within the operating ranges of otherreception/transmission components, the GCs 30, 32 adjust the gain on theRX and TX signals.

To control the gain parameters for the GCs 30, 32, a GC controller 38 isused. As shown in FIG. 1, the GC controller 38 uses a power control bus,such as a sixteen line bus 34, 36, to send a gain value for the TX 36and RX 34 signals, such as eight lines for each. Although the powercontrol bus lines 34, 36 allow for a fast data transfer, it requireseither many pins on the GCs 30, 32 and the GC controller 38 or manyconnections between the GCs 30, 32 and GC controller 38 on an integratedcircuit (IC), such as an application specific IC (ASIC). Increasing thenumber of pins requires additional circuit board space and connections.Increasing IC connections uses valuable IC space. The large number ofpins or connections may increase the cost of a bus depending on theimplementation.

Accordingly, it is desirable to have other data transfer approaches.

SUMMARY

A hybrid serial/parallel bus interface has a data block demultiplexingdevice. The data block demultiplexing device has an input configured toreceive a data block and demultiplexes the data block into a pluralityof nibbles. For each nibble, a parallel to serial converter converts thenibble into serial data. A line transfers each nibble's serial data. Aserial to parallel converter converts each nibble's serial data torecover that nibble. A data block reconstruction device combines therecovered nibbles into the data block.

BRIEF DESCRIPTION OF THE DRAWING(S)

FIG. 1 is an illustration of a RX and TX GC and a GC controller.

FIG. 2 is a block diagram of a hybrid parallel/serial bus interface.

FIG. 3 is a flow chart for transferring data blocks using a hybridparallel/serial bus interface.

FIG. 4 illustrates demultiplexing a block into a most significant andleast significant nibble.

FIG. 5 illustrates demultiplexing a block using interleaving.

FIG. 6 is a block diagram of a bi-directional hybrid parallel/serial businterface.

FIG. 7 is a diagram of an implementation of one bi-directional line.

FIG. 8 is a timing diagram illustrating start bits.

FIG. 9 is a block diagram of a function controllable hybridparallel/serial bus interface.

FIG. 10 is a timing diagram of start bits for a function controllablehybrid parallel/serial bus interface.

FIG. 11 is a table of an implementation of start bits indicatingfunctions.

FIG. 12 is a block diagram of a destination controlling hybridparallel/serial bus interface.

FIG. 13 is a table of an implementation of start bits indicatingdestinations.

FIG. 14 is a table of an implementation of start bits indicatingdestinations/functions.

FIG. 15 is a block diagram of a destinations/functions controllinghybrid parallel/serial bus interface.

FIG. 16 is a flow chart for start bits indicatingdestinations/functions.

FIG. 17 is a block diagram for a positive and negative clock edge hybridparallel/serial bus interface.

FIG. 18 is a timing diagram for a positive and negative clock edgehybrid parallel/serial bus interface.

FIG. 19 is a block diagram of a 2-line GC/GC controller bus.

FIG. 20 is a block diagram of a 3-line GC/GC controller bus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 is a block diagram of a hybrid parallel/serial bus interface andFIG. 3 is a flow chart of hybrid parallel/serial bus interface datatransfer. A data block is to be transferred across the interface fromnode 1 50 to node 2 52, (54). A data block demultiplexing device 40receives the block and demultiplexes it into i nibbles for transfer overi data transfer lines 44, (56). The value for i is based on a tradeoffbetween number of connections and transfer speed. One approach todetermine i is to first determine a maximum latency permitted totransfer the data block. Based on the allowed maximum latency, a minimumnumber of lines required to transfer the block is determined. Using theminimum number of lines, the lines used to transfer the data is selectedto be at least the minimum. The lines 44 may be the pins and theirassociated connections on a circuit board or connections on an IC. Oneapproach to demultiplex into nibbles divides the block into a mostsignificant to a least significant nibble. To illustrate for an eightbit block transfer over two lines as shown in FIG. 4, the block isdemultiplexed into a four bit most significant nibble and a four bitleast significant nibble.

Another approach interleaves the block across the i nibbles. The first ibits of the block become the first bit in each nibble. The second i bitsbecome the second bit in each nibble and so on until the last i bits. Toillustrate for an eight bit block over two connections as shown in FIG.5, the first bit is mapped to the first bit of nibble one. The secondbit is mapped to the first bit of nibble two. The third bit is mapped tothe second bit of nibble one and so on until the last bit is mapped tothe last bit of nibble two.

Each nibble is sent to a corresponding one of i parallel to serial (P/S)converters 42, (58), converted from parallel bits to serial bits, andtransferred serially across its line, (60). On the opposing end of eachline is a serial to parallel (S/P) converter 46. Each S/P converter 46converts the transmitted serial data into its original nibble, (62). Thei recovered nibbles are processed by a data block reconstruction device48 to reconstruct the original data block, (64).

In another, bidirectional, approach, the i connections are used totransfer data in both directions as shown in FIG. 6. Information datamay be transferred in both directions or information may be sent in onedirection and an acknowledgment sent back in the other direction. A datablock for transfer from node 1 50 to node 2 52 is received by the datablock demultiplexing and reconstruction device 66. The demultiplexingand reconstruction device 66 demultiplexes the block into i nibbles. iP/S converters 68 convert each nibble into serial data. A set ofmultiplexers (MUXs)/DEMUXs 71 couples each P/S converter 68 to acorresponding one of the i lines 44. At node 2 52, another set ofMUXs/DEMUXs 75 connects the lines 44 to a set of S/P converters 72. TheS/P converters 72 convert the received serial data of each nibble intothe originally transmitted nibbles. The received nibbles arereconstructed by a data block demultiplexing and reconstruction device76 into the original data block and output as the received data block.

For blocks transferred from Node 2 52 to Node 1 50, a data block isreceived by the data block demultiplexing and reconstruction device 76.That block is demultiplexed into nibbles and the nibbles are sent to aset of P/S converters 74. The P/S converters 74 convert each nibble intoserial format for transfer across the i lines 44. A Node 2 set ofMUXs/DEMUXs 75 couples the P/S converters 74 to the i lines 44 and aNode 1 set of MUXs/DEMUXs 71 couples the lines 44 to i S/P converters70. The S/P converters 70 convert the transmitted data into its originalnibbles. The data block demultiplexing and reconstruction device 66reconstructs the data block from the received nibbles to output thereceived data block. Since data is only sent in one direction at a time,this implementation operates in a half duplex mode.

FIG. 7 is a simplified diagram of one implementation of bidirectionalswitching circuits. The serial output from the node 1 P/S converter 68is input into a tri-statable buffer 78. The buffer 78 has another inputcoupled to a voltage representing a high state. The output of the buffer78 is the serial data which is sent via the line 85 to a Node 2tri-statable buffer 84. A resistor 86 is coupled between the line 85 andground. The Node 2 buffer 84 passes the serial data to a Node 2 S/Pconverter 72. Similarly, the serial output from the Node 2 P/S converter74 is input into a tri-statable buffer 72. That buffer 72 also havinganother input coupled to a high voltage. The serial output of thatbuffer 82 is sent via the line 85 to a Node 1 tri-statable buffer 80.The Node 1 buffer 80 passes the serial data to a Node 1 S/P converter70.

In another implementation, some of the i lines 44 may transfer data inone direction and the other i lines 44 transfer data in anotherdirection. At Node 1 50, a data block is received for transmission toNode 2 52. Based on the data throughput rate required for the block andthe traffic demand in the opposite direction, j, being a value from 1 toi, of the connections are used to transfer the block. The block isbroken into j nibbles and converted to j sets of serial data using j ofthe i P/S converters 68. A corresponding j Node 2 S/P converters 72 andthe Node 2 data block separation and reconstruction device 76 recoversthe data block. In the opposite direction, up to i-j or k lines are usedto transfer block data.

In a preferred implementation of the bidirectional bus for use in a gaincontrol bus, a gain control value is sent in one direction and anacknowledgment signal is sent back. Alternately, a gain control value issent in one direction and a status of the gain control device in theother direction.

One implementation of the hybrid parallel/serial interface is in asynchronous system and is described in conjunction with FIG. 8. Asynchronous clock is used to synchronize the timing of the variouscomponents. To indicate the start of the data block transfer, a startbit is sent. As shown in FIG. 8, each line is at its normal zero level.A start bit is sent indicating the beginning of the block transfer. Inthis example, all the lines send a start bit, although it is onlynecessary to send a start bit over one line. If a start bit, such as aone value, is sent over any line, the receiving node realizes that theblock data transfer has begun. Each serial nibble is sent through itscorresponding line. After transfer of the nibbles, the lines return totheir normal state, such as all low.

In another implementation, the start bits are also used as an indicatorof functions to be performed. An illustration of such an implementationis shown in FIG. 9. As shown in FIG. 10, if any of the connections'sfirst bits are a one, the receiving node realizes block data is to betransferred. As shown in the table of FIG. 11 for a GC controllerimplementation, three combinations of start bits are used, “01,” “10”and “11.” “00” indicates a start bit was not sent. Each combinationrepresents a function. In this illustration, “01” indicates that arelative decrease function should be performed, such as decreasing thedata block value by 1. A “10” indicates that a relative increasefunction should be performed, such as increasing the data block valueby 1. A “11” indicates an absolute value function, where the blockmaintains the same value. To increase the number of available functions,additional bits are used. For example, 2 starting bits per line aremapped to up to seven (7) functions or n starting bits for i lines aremapped up to i.sup.n+1-1 functions. The processing device 86 performsthe function on the received data block as indicated by the startingbits.

In another implementation as shown in FIG. 12, the start bits indicate adestination device. As illustrated in FIG. 13 for a two destinationdevice/two line implementation, the combination of start bits relates toa destination device 88-92 for the transferred data block. A “01”represents device 1; a “10” represents device 2; and a “11” representsdevice 3. After receipt of the start bits of the data blockreconstruction device 48, the reconstructed block is sent to thecorresponding device 88-92. To increase the number of potentialdestination devices, additional start bits may be used. For n startingbits over each of i lines, up to i.sup.n+1-1 devices are selected.

As illustrated in the table of FIG. 14, the start bits may be used torepresent both function and destination device. FIG. 14 shows a threeconnection system having two devices, such as a RX and TX GC. Using thestart bit for each line, three functions for two devices is shown. Inthis example, the start bit for line 1 represents the target device, a“0” for device 1 and a “1” for device 2. The bits for connections 2 and3 represent the performed function. A “11” represents an absolute valuefunction; a “10” represents a relative increase function; and a “01”represents a relative decrease. All three start bits as a zero, “000,”is the normal non-data transfer state and “001” is not used. Additionalbits may be used to add more functions or devices. For n starting bitsover each of i lines, up to i.sup.n+1-1 function/device combinations arepossible.

FIG. 15 is a block diagram for a system implementing the start bitsindicating both function and destination device. The recovered nibblesare received by the data block reconstruction device 48. Based on thereceived start bits, the processing device 86 performs the indicatedfunction and the processed block is sent to the indicated destinationdevice 88-92.

As shown in the flow chart of FIG. 16, the start bits indicating thefunction/destination are added to each nibble, (94). The nibbles aresent via the i lines, (96). Using the start bits, the proper function isperformed on the data block, the data block is sent to the appropriatedestination or both, (98).

To increase the throughput in a synchronous system, both the positive(even) and negative (odd) edge of the clock are used to transfer blockdata. One implementation is shown in FIG. 17. The data block is receivedby a data block demultiplexing device 100 and demultiplexed into two(even and odd) sets of i nibbles. Each set of the i nibbles is sent to arespective set of i P/S devices 102, 104.

As shown in FIG. 17, an odd P/S device set 102, having i P/S devices,has its clock signal inverted by an invertor 118. As a result, theinverted clock signal is half a clock cycle delayed with respect to thesystem clock. A set of i MUXs 106 select at twice the clock rate betweenthe even P/S device set 104 and the odd P/S device set 102. Theresulting data transferred over each connection is at twice the clockrate. At the other end of each connection is a corresponding DEMUX 108.The DEMUXs 108 sequentially couple each line 44 to an even 112 and odd110 buffer, at twice the clock rate. Each buffer 112, 110 receives acorresponding even and odd bit and holds that value for a full clockcycle. An even 116 and odd 114 set of S/P devices recover the even andodd nibbles. A data block reconstruction device 122 reconstructs thedata block from the transferred nibbles.

FIG. 18 illustrates the data transfer over a line of a system using thepositive and negative clock edge. Even data and odd data to betransferred over line 1 is shown. The hatching indicates the negativeclock edge data in the combined signal and no hatching the even. Asshown, the data transfer rate is increased by two.

FIG. 19 is a preferred implementation of the hybrid parallel/serialinterface used between a GC controller 38 and a GC 124. A data block,such as having 16 bits of GC control data (8 bits RX and 8 bits TX), issent from the GC controller 38 to a data block demultiplexing device 40.The data block is demultiplexed into two nibbles, such as two eight bitnibbles. A start bit is added to each nibble, such as making 9 bits pernibble. The two nibbles are transferred over two lines using two P/Sconverters 42. The S/P converters 46 upon detecting the start bitsconvert the received nibbles to parallel format. The data blockreconstruction device reconstructs the original 16 bits to control thegain of the GC 124. If a function is indicated by the start bits, suchas in FIG. 11, the AGC 124 performs that function on the received blockprior to adjusting the gain.

FIG. 20 is another preferred implementation for a hybrid parallel/serialconverter, using three (3) lines, between a GC controller 38 and a RX GC30 and TX GC 32. The GC controller 38 sends a data block to the GC 30,32 with proper RX and TX gain values and start bits, such as per FIG.14. If the start bits per FIG. 14 are used, Device 1 is the RX GC 30 andDevice 2 is the TX GC 32. The data block demultiplexing device 40demultiplexes the data block into three nibbles for transfer over thethree lines. Using the three P/S converters 42 and three S/P converters46, the nibbles are transferred serially over the lines and convertedinto the original nibbles. The data block reconstruction device 48reconstructs the original data block and performs the function asindicated by the start bits, such as relative increase, relativedecrease and absolute value. The resulting data is sent to either the RXor TX GC 30, 32 as indicated by the start bits.

1. Apparatus for use in a wireless unit for controlling signal levels ofwireless messages sent and received by the wireless unit, comprising: atransmitter (TX) gain control device (TX GCD) and receiver (RX) gaincontrol device (RX GCD) for respectively controlling a gain of signalsrespectively sent by and received by said devices; a GC controller forproducing a data block having n data bits representing a gain value; ilines each configured to transfer portions of the data block from the GCcontroller to a given one of the TX GCD and RX GCD, where 1<i<n; a datablock converting device for converting the data block into said datablock portions, each data block portion having a start bit; each datablock portion being applied to an associated one of said i lines; thedata block portions from said i lines being combined to reconstruct theoriginal data block; the data block being transferred to the given GCDbased on the collective states of the start bits; and the given GCDreceiving the data block and adjusting a gain of the signal handled bythe given GCD using the gain value of the data block to thereby maintainthe signal handled by the given GCD at a gain value determined by the GCcontroller.
 2. The apparatus of claim 1 further comprising: i serialconverter devices each associated with a first end of the i lines fortransferring each block portion over its associated line in serialfashion; and i parallel converter devices each associated with a secondend of the i lines for converting the block portion transferred inserial fashion to the original data block portion; and the data blockportions being combined by a data block reconstruction device.
 3. Theapparatus of claim 1 wherein the TX GCD is configured to receive thesignals to be transmitted and amplifies the signals to be transmittedbased on the data block.
 4. The apparatus of claim 1 wherein the RX GCDis configured to receive the signals sent to the wireless unit andamplifies the signals sent to the wireless unit based on the data block.5. The apparatus of claim 1 wherein the states of the start bitsindicate a mathematical function.
 6. The apparatus of claim 5 whereinthe mathematical functions indicated by the states of the start bitsinclude one of a relative increase of a prior gain value, a relativedecrease of a prior gain value and an absolute value to thereby avoid aneed to provide a new gain value when a change in gain value is needed.7. The apparatus of claim 2 wherein the i serial converters are parallelto serial converters.
 8. The apparatus of claim 2 wherein the i parallelconverters are serial to parallel converters.
 9. The apparatus of claim1 wherein the states of the start bits are either one of two binarystates.
 10. The apparatus of claim 1 wherein i is a number selected toenable the i start bits to simultaneously represent both the GCD toreceive the data block and the function to be performed by the data ofthe data block.
 11. The apparatus of claim 1 wherein i is at least 3.12. A method for use by a wireless unit for controlling signal levels ofwireless messages sent by a transmitter gain control device (TX GCD) andreceived by receiver gain control device (RX GCD) of the wireless unit,comprising: producing a data block of n data bits, states of the n databits collectively representing a gain value; converting the data blockinto i data block portions where 1<i<n; providing each data blockportion with a start bit; transferring each of the i data block portionsand their associated start bits over an associated one of i lines;combining the data block portions transferred over said i lines toreconstruct the original data block; coupling the combined data block toone of said TX GCD and RX GCD based on the collective states of thestart bits; and adjusting a gain of the signal handled by said one ofsaid TX GCD and RX GCD based on the gain value of the combined datablock.
 13. The method of claim 12 further comprising: applying each ofthe i data block portions to an associated one of the i lines in aserial fashion; converting the data block portions applied to the ilines applied to the i lines in serial fashion back to their originalformat; and applying the reconstructed data block to the selected GCD tocontrol a gain of the message signal based on a gain value representedby the collective states of the reconstructed data block.
 14. The methodof claim 12, the TX GCD receiving signals to be transmitted andamplifying the signals to be transmitted based on the reconstructed datablock.
 15. The method of claim 12, the RX GCD receiving signals sent tothe wireless unit and amplifying the signals sent to the wireless unitbased on the reconstructed data block.
 16. The method of claim 12wherein the states of the start bits indicate a mathematical function.17. The method of claim 16 wherein the mathematical functions indicatedby the states of the start bits include one of a relative increase of aprior gain value, a relative decrease of a prior gain value and anabsolute value to thereby avoid a need to provide a new gain value whena change in gain value is needed.
 18. The method of claim 13 wherein thedata block portions are in a parallel format and the data block portionseach undergo conversion to serial format employing parallel to serialconverters.
 19. The method of claim 13 wherein the serial format dataapplied to the i lines are converted to parallel format employing serialto parallel converters.
 20. The method of claim 12 wherein the states ofthe start bits are either one of two binary states.
 21. The method ofclaim 12, comprising selecting a number for wherein i to enable the istart bits to simultaneously represent both the GCD to receive the datablock and the function to be performed by the data of the data block.22. The method of claim 21 comprising selecting the number for i to beat least
 3. 23. The method of claim 21, comprising selecting the numberfor i to enable the start bits to collectively represent at least 3different functions and 2 different GCDs.